A method in connection with reverse stranding, comprising drawing conductors, such as filaments, conductor elements, bundles of conductors, optical fibers or the like, of a cable to be produced, particularly of a block-insulated cable, through a stationary divider means, peripheral tubes peripherally surrounding a central tube and twistable around the central tube recurrently in opposite directions and a twisting means rotatable in opposite directions, into a stranding nozzle or similar. The invention also relates to an arrangement in connection with reverse stranding.
A wide variety of methods and arrangements are known in connection with reverse stranding. The solution disclosed in U.S. Pat. No. 4,974,408 may be mentioned as an example of such prior art solutions. The solution disclosed in this U.S. patent operates completely faultlessly in most circumstances, but if one desires to manufacture block-insulated cables, PCM cables for instance, by means of such an arrangement, then said solution cannot be used as such, as the feed of a strip serving as an intermediate shield in the cable cannot be realized with said apparatus. The block-insulated cables referred to above are digital cables usually employed for duplex data transmission, and therefore the discrete main blocks are separated from one another by an S-shaped metallic intermediate shield. The intent is to correct near-end crosstalk, since both transmission directions use the same frequency band and, furthermore, the difference in level between the output and input is great.
Several different solutions have been developed for the longitudinal strip winding of a block-insulated cable. The solution described in U.S. Pat. No. 4,428,787 may be mentioned as an example of an arrangement for longitudinal strip winding known in this field. The solution of this U.S. patent is intended only and exclusively for carrying out longitudinal strip winding; for instance stranding cannot be performed by means of this arrangement.
The drawback of the prior art has been the large quantity of devices required in the manufacture of cables of the above type. Heretofore it has not been possible to perform reverse stranding and longitudinal strip winding with the same equipment. Furthermore, it has been difficult to connect the strip winding to other steps. This has increased the costs and complicated the production.